@ wvdp: so what is the problem? In The Netherlands we often have this kind of apartment buildings. Every apartment has its own address. In Utrecht we have one student building with over 600 addresses. The tagging has been discussed with the Data Working Group which does not want these nodes on top of each other, so what you see here is the actual solution. If you want to check if the housenumbers are there, please feel free to check it out on the Burgwal. Don't remove the housenumbers, since they are actually there.